Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Design of Hand-holes in tubular members - Highway signs and structures.

Design of Hand-holes in tubular members - Highway signs and structures.

Design of Hand-holes in tubular members - Highway signs and structures.

I have checked previous threads dealing with the subject and there was very useful comments regarding the hand-hole reinforceemnt for the bending and axial forces. However, the torsional properities of the tubular member (J) decreases drastically (maybe by a thousand fold) when any tiny cut-out is introduced. No reinforcement to the hand-hole can ever (practically) reinstate this as you can all appreciate.

I figure that:

1. For a relatively small hand-hole in a large diameter member, the torsional (any other)stresses will simply be redistributed around the hole and the issue becomes a matter stress concentration around the hole. For bending and axial forces, the hole can simply be reinforced to restore the original section properties Ax, Iz & Iy but for torsional property J which cannot be restored by reinforcement, the stress concentrations around the hand-hole will have to be assessed. I have not found any literature yet that addresses the assessment of the stress concentrations around an opening in a round hollow member (only stress concentration for plates in unitform tension with a hole are widely available).

2. As the hole gets larger in comparision with the diameter of the member (especially in the direction parallel to the member axis), the torsion becomes more and more of an issue as the shear stress re-distribution around the hand-holes becomes impossible and the member would have to resist the torsion as if it is an "open" section (e.g. like a channel) which is very poor in torsion resistance and is likely to fail in torsion. Again, for bending and axial forces, the larger hole can always be reinforced to compensate for the loss of area, Ix & Iy.

Thus short of doing a finite element analysis with a fine mesh for the member with the hand-hole, has anyone found literature that helps in the design of tubular members with hand-holes subjected to torsion?

RE: Design of Hand-holes in tubular members - Highway signs and structures.

Wind-generation towers and column skirts use heavy barstock 'banding' wrapped around the ID of the opening. These work well to handle the bending and torsional stresses in the 'real world'. If I was presented [stuck] with your problem, I would add enough inch^3 of bar to 'replace the hole', just like a standard repad calc.

It's kind of a Sect. VIII Div. 1 approach: minimal calc's, and rules-of-thumb that have been proven to work.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close